Errror message after deleting sub wiki

Favorites extension is installed in every sub wiki.

We deleted one sub wiki in our XWiki farm.

No one had a favorite pointing to this sub wiki (a page in this sub wiki).

Now we have following error message behing the 3 dots of the page:

Complete stacktrace as attachment.

Workaround:

• Uninstall favorites extension in all sub wikis and its dependencies
  • error still exists
• Restart XWiki
  • error is gone
• Reinstall favorites application as before
  • still no error